Protective cover assembly with reverse buckling disc

Abstract

A protective cover assembly for a fluid end of a plunger-type pump or other positive displacement pump. The protective cover assembly includes a cover adapted to fit in an open end of the fluid end of the pump. The cover comprises a convex or domed center portion adapted for buckling away from a plunger of the pump when pressure in the pump exceeds a predetermined level and further comprises an outer portion. A cover retainer is engageable with the open end of the fluid end of the pump and is adapted for clamping the outer portion of the cover to the fluid end. A seal is provided between the outer portion of the cover and the fluid end. The convex center portion of the cover has a convex surface generally facing the plunger, and the convex surface is preferably hemispherical. In one embodiment, the convex center portion has a substantially constant cross-sectional thickness, and in an alternate embodiment, the convex center portion has an enlarged section adapted for affecting a pressure level required for buckling the convex portion. A method of preventing overpressure in a fluid end of a plunger-type pump using the protective cover assembly is also disclosed.

What is claimed is: 
     
       1. A protective cover assembly for a plunger-type pump having a fluid end which includes a cylinder with a reciprocating plunger therein, said plunger creating a cyclic pressure differential for pumping a fluid therethrough, said assembly comprising: a cover positionable in an outer end of said fluid end, said cover including buckling relief means of a hemispherical configuration having a convex portion disposed towards said plunger, for buckling in a direction away from said plunger without rupturing when a pressure within said cylinder acting on said cover exceeds a first predetermined level, thereby relieving said pressure without venting fluid externally of said pump,   wherein the hemispherical configuration increases the useful life of said relief means by minimizing the effects of stress exerted thereon by said cyclic pressure differential, and by providing a streamlined flow path for said fluid within said fluid end; and retainer means, having an aperture therethrough, for retaining said cover in said outer end,     wherein said said aperture externally vents said fluid after said relief means is ruptured due to pressure within said cylinder exceeding a second predetermined level which is greater than said first predetermined level.   
     
     
       2. The assembly of claim 1 wherein said relief means has a substantially constant thickness. 
     
     
       3. The assembly of claim 1 further comprising sensing means for sensing buckling of said buckling relief means and interrupting power delivered to said pump. 
     
     
       4. The assembly of claim 1 wherein said retainer means is characterized by a cover retainer engaged with said fluid end and having a frustoconical inner wall for containing said buckling relief means and dissipating kinetic energy thereof in the event of rupture of said buckling relief means. 
     
     
       5. The assembly of claim 1 further comprising sealing means disposed between said cover and said fluid end. 
     
     
       6. The assembly of claim 1 wherein said relief means has an enlarged section for setting said first predetermined pressure level and said second predetermined pressure level. 
     
     
       7. The assembly of claim 6 wherein: said relief means has a concave surface on a side of said cover opposite said plunger; and   said enlarged section is formed by a substantially flat surface truncating said concave surface.